Add a template link template function for getting a permalink to the blog index

[ericlewis]

There is currently no link template function to get the blog index permalink easily, although we have a plurality for more granular blog archives (get_day_link(), get_search_link(), etc).

[ericlewis]

I'll suggest get_blog_url() to match the general naming conventions of other link template functions ( e.g. get_admin_url() ).

I'm sure there are a multitude of setups that I am unfamiliar with that go back to the 1.0 days we'll have to cover for backwards compatibility, so excuse the naive in my starter-code suggestion:

function get_blog_url() {
	// If a page is set to show the blog index, return that.
	if ( get_option( 'page_for_posts' ) ) 
		return get_permalink( get_option( 'page_for_posts' ) );

	// If there is a page on front, there is no blog index.
	if ( 'posts' === get_option( 'show_on_front' ) )
		return site_url();

	// Otherwise, there is no blog index.
	return false;
}

[SergeyBiryukov]

Duplicate of #19902.

[ericlewis]

Wow, I opened up a ticket that's a duplicate of another ticket I've already commented on :P